1. Field of the Invention
The present invention relates to organic light-emitting devices including fused polycyclic compounds.
2. Description of the Related Art
An organic light-emitting device includes an anode, a cathode, and a thin film containing an organic fluorescent compound therebetween. Electrons and holes are injected from the electrodes into the fluorescent compound to generate excitons. As the excitons return to the ground state, the organic light-emitting device emits light.
For applications such as displays for mobile devices, it is necessary that organic light-emitting devices themselves have low power consumption. In particular, intensive research and development has been conducted in hole injection/transport materials used for hole injection layers and hole transport layers, which are peripheral layers for light-emitting layers, because they contribute to the drive voltage, luminous efficiency, and life of the organic light-emitting devices. To date, however, the above problem has yet to be sufficiently addressed.
As one solution to the above problem, Japanese Patent Laid-Open No. 2009-152529 (Patent Document 1) proposes that a fluoranthene derivative be used as a material for hole injection layers in organic light-emitting devices. In addition, Japanese Patent Laid-Open No. 2008-198769 (Patent Document 2) proposes that a charge-generating layer be formed on an anode with a combination of a hole transport material with an aromatic carboxylic acid derivative, which has high electron-accepting ability. Such derivatives, however, need further improvements from viewpoints such as color of light, efficiency, luminance, and durability.
On the other hand, Japanese Patent Laid-Open No. 2009-70983 (Patent Document 3) proposes that a compound having an acenaphthofluoranthene backbone with an aromatic ring fused thereto be used as an organic thin-film transistor (TFT) material.